Actor Dylan McDermott solved the mystery of his mother's tragic death, 45 years later.

McDermott was 5-years-old when his mother Diana McDermott died. At the moment of her death he was standing at the home's door because he had been kicked out of his home by his mother's boyfriend John Sponza, a well known gangster and heroin addict.

He heard shouting and a gunshot. His mother suffered a fatal gun wound to the head and died. The death was ruled an accident. Sponza was reportedly cleaning his gun when it went off. Dylan and his sister Robin, who was then six months old, were taken in by their grandmother, Avis Marino.

McDermott requested the investigation to be reopenened in 2011 and found out that his mother was murdered by Sponza and that police covered up Sponza's involvement in the crime and ruled the death accidental, according to the newspaper Republican-American.

"In order for me to survive and to get where I am today, I needed to bury that moment in my life deep within myself," the actor told police, according to the newspaper.

"I’ve come to the point in my life where I’m able to begin to process all of this," he told police recently when he requested the investigation of the case to be reopened, the paper reports.

McDermott is best known for his role as Bobby Donnell on "The Practice," for which he earned a Golden Globe Award for Best Actor. He also appeared in the film "Line of Fire" with Clint Eastwood in 1993.

He currently stars in "American Horror Story" on FX.